About 4% of people worldwide have been diagnosed with an anxiety disorder.
Photograph: Josh Edelson/AFP/Getty

Women are nearly twice as likely to experience anxiety as men, and people of both sexes under 35 are more likely to be affected than older people, according research that combined evidence from 48 previous reviews of studies into the condition.

The researchers also found that those suffering from diseases including cancer, stroke and multiple sclerosis have a higher chance of experiencing symptoms of anxiety than healthy individuals. They say the research could help to identify those at risk of anxiety, and make sure support is available.

“So much research and so much focus has been around depression and, while that is an important disorder, so is anxiety,” said Olivia Remes, from Cambridge University, who led the research. “Anxiety can also lead to disability, impairment [and] it can increase the risk for suicide.”

It is estimated there were 8.2m cases of anxiety in the UK in 2013. Symptoms can include a feeling of dread, muscular tension, sweating and the avoidance of social situations.

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The research, published in the journal Brain and Behaviour, examines data from 48 reviews to explore trends in anxiety across different groups of people, including those with chronic diseases, gamblers and pregnant women.

“It provides an indication of who is at risk from anxiety, who is most likely to develop it,” said Remes. “When we know who is most likely to have it, then we can better target our health service’s resources, interventions, screening and prevention efforts.”

The findings reveal that about 4% of people worldwide have an anxiety disorder – a figure that remained almost constant between 1990 and 2010.

But, as Remes points out, these figures only relate to those actually diagnosed with anxiety disorders, and refer to the general population. “Many more people are affected by anxiety symptoms, which can have important negative consequences,” she said.

Women were twice as likely to experience anxiety than men, with men and women under the age of 35 more likely to be affected by anxiety than older people. “It might be that younger people are more likely to be exposed to anxiety provoking situations – they are more likely to be in employment and they are more likely to be exposed because of that to a higher number of social interactions,” said Remes.

In addition, people with chronic diseases were more likely to have anxiety compared to those who were healthy. Up to a third of patients with MS had an anxiety disorder, while the figure ranged between 18% and 35% for stroke patients. Cancer patients also had a high chance of anxiety, with up to 79% of those in the later stages of the disease experiencing symptoms.

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But it is not clear whether this trend is simply down to the worry of being sick. “It could be that medication for certain diseases could be triggering anxiety, it could also be that the disease itself might be triggering this anxiety, or people with anxiety might be more likely to experience inflammation in their body – and this inflammation can then give rise to later physical diseases,” said Remes.

While Remes noted that some of the reviews looked at symptoms of anxiety, others looked at those diagnosed with anxiety disorders, with few exploring specific disorders. The way anxiety was measured also varied between studies, she said, highlighting the need for consistent and reliable methods.

Differences in the way people from different cultures experienced anxiety should also be taken into account, she said.

David Clark, professor of experimental psychology at the University of Oxford who was not involved in the study, said the link between anxiety and chronic disease highlighted the need to link the treatment of mental and physical health conditions in patients. “This is important because, at the moment, people with long-term physical health conditions and also mental health problems often aren’t well served by the NHS because you go to one place for your physical health care and another for your mental health care.”

A coordinated approach, Clark said, would be a positive step both for patients and the NHS. “[For] long term physical health conditions, the physical management costs more if someone has got anxiety and depression,” he said. “It makes sense for health services to address this not only because it’s of great patient benefit but it also will be more economical for the health services themselves.”

Stephen Buckley, the head of information at mental health charity Mind, said, “The reasons for experiencing anxiety vary from person to person, but might include having low self-esteem, trying to take on lots of different responsibilities or past and childhood experiences. Men and women may also deal with mental health problems in different ways: our research showed that women may talk more openly about their feelings and be more likely to turn to friends and family for support, whereas men may find other ways to unwind like watching TV or using drugs and alcohol.

“If you feel that you or someone you know may have anxiety it is important to speak to someone, such as your GP or friend or family member, as soon as possible so you are not alone in dealing with it and can get the right help and support.”